The present invention relates to a conductive film that is used in a three-dimensional shape, a display device including the conductive film, and a method for evaluating and determining a wiring pattern of the conductive film.
Examples of a conductive film that is provided on a display unit of a display device (hereinafter, also referred to as a “display”) of, for example, a mobile phone include a conductive film for shielding electromagnetic waves and a conductive film for touch panels (for example, see JP2009-117683A, JP2011-216379A, JP2012-163933A, JP2012-163951A, and JP2012-164648A).
JP2009-117683A filed by the inventors discloses a technique which automatically select a second pattern that is generated from second pattern data in which the relative distance between the spectrum peaks of two-dimensional Fourier spectrums (2DFFT Sp) in the pattern data of a first pattern, such as a pixel array pattern (for example, a black matrix (hereinafter, also referred to as BM) pattern) of a display and the pattern data of the second pattern, such as an electromagnetic wave shielding pattern, is greater than a predetermined spatial frequency, for example, 8 cm−1.
Therefore, according to the technique disclosed in JP2009-117683A, it is possible to automatically select an electromagnetic wave shielding pattern which can prevent the occurrence of moire and avoid an increase in surface resistivity or the deterioration of transparency.
JP2011-216379A filed by the inventors discloses a transparent conductive film which has a mesh pattern including a plurality of polygonal meshes. In the transparent conductive film, the mesh pattern is formed such that, in the centroid spectrum of each mesh, average intensity in a frequency band higher than a predetermined spatial frequency, for example, a spatial frequency at which the human visual response characteristics are 5% of the maximum response is higher than average intensity in a frequency band lower than the predetermined spatial frequency.
Therefore, according to the technique disclosed in JP2011-216379A, it is possible to provide a transparent conductive film which can reduce noise granular feeling caused by the pattern, can significantly improve the visibility of the object to be observed, and has a stable conduction performance even after being cut.
JP2012-163933A filed by the inventors discloses a conductive pattern having a rhombic-shaped mesh formed by thin metal wires. In the conductive pattern, the ratio of the lengths of two diagonal lines of the rhombus of an opening in each mesh is limited to a predetermined range. JP2012-163951A discloses a mesh pattern formed by thin metal wires. In the mesh pattern, the inclination angle of the thin metal wire with respect to the direction in which the pixels of a display device are arranged is limited to a predetermined range. JP2012-164648A discloses a rhombic-shaped mesh pattern formed by thin metal wires. In the mesh pattern, the vertex angle of the rhombus of an opening in each mesh is limited to a predetermined range. Therefore, even when the pattern is attached to a display panel, moire is less likely to occur and it is possible to produce products with high yield.